Alert archive / Iowa / Flash Flood Warnings in 1987

Flash Flood Warning 4, NWS Des Moines, IA

July 12, 1987Dallas County, Polk County, Iowa

NWS Des Moines, IA issued this flash flood warning at Jul 12, 1987, 3:06 AM CDT for Dallas County, Polk County, Iowa. It was in force for 4 hr.

The area

The counties it named.

The facts

Issued
Jul 12, 1987, 3:06 AM CDT (08:06 UTC)
Expired
Jul 12, 1987, 7:00 AM CDT
In force
4 hr
Issued by
NWS Des Moines, IA
Area
Whole counties

Counties Dallas County, IA, Polk County, IA

The radar

The WSR-88D network and its archive begin in 1991, so there is no radar volume for this alert.

The nearest sounding before it

Omaha, NE (KOAX), launched 00:00Z, 8.1 hours before the alert went out and 217 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-pSkew-T log-p diagram, Omaha, NE at 00:00Z on 1987-07-12Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Omaha, NE at 00:00Z on 1987-07-12The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 98 square meters per square second.1939Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.
Mixed-layer CAPE
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
3602 m above ground
0-6 km bulk shear
20 kt
0-1 km storm-relative helicity
98 m²/s²
0-3 km storm-relative helicity
145 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

000 
TTAA00 KDSM 120808
FFWDSM
IAC153-049-121200-
<PQ<
BULLETIN - IMMEDIATE BROADCAST REQUESTED/EBS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE DES MOINES IA
306 AM CDT SUN JUL 12 1987

THE NATIONAL WEATHER SERVICE HAS ISSUED A FLASH FLOOD WARNING
EFFECTIVE UNTIL 700 AM CDT FOR PEOPLE IN THE FOLLOWING COUNTIES OF

CENTRAL IOWA...
 WESTERN POLK AND EASTERN DALLAS

A FLASH FLOOD WARNING MEANS FLOODING IS IMMINENT OR IS OCCURRING.
TAKE NECESSARY PRECAUTIONS IMMEDIATELY.

A FLASH FLOOD WARNING IS BEING ISSUED FOR WALNUT CREEK IN THE
WESTERN PARTS OF THE DES MOINES AREA.

AT 300 AM CDT THE CREEK WAS FLOODING IN DALLAS COUNTY AND ALSO
WAS BANKFULL AT 142ND STREET...132ND STREET...AND AT BUFFALO
ROAD IN WEST DES MOINES.  AT 63RD STREET THE CREEK WAS AT 10.8
FEET AT 63RD STREET.

THE CREEK WILL CONTINUE TO RISE AND IT WILL REACH A COUPLE FEET
ABOVE BANKFULL IN MOST AREAS.

THE FLOODING WILL NOT BE NEARLY AS SIGNIFICANT AS THE FLOOD OF
MAY 1986.

ONE POSITIVE NOTE...THE HEAVY RAINS ARE OVER FOR THIS AREA.
LIGHT SHOWERS WILL BE AROUND DURING THE MORNING HOURS.

PEOPLE IN FLOOD PRONE OR LOW LYING AREAS SHOULD MOVE TO HIGHER GROUND
AT ONCE.  ACT QUICKLY..AS FLOOD WATERS OFTEN RISE RAPIDLY.

IF YOU ARE DRIVING..DO NOT TRY TO DRIVE THROUGH FLOOD WATERS OF
UNKNOWN DEPTH.  IF YOUR VEHICLE STALLS..ABANDON IT IMMEDIATELY
AND SEEK HIGHER GROUND.

DO NOT ATTEMPT TO CROSS A FLOWING STREAM ON FOOT WHERE THE WATER
IS ABOVE YOUR KNEES4.

ADAMS

What forecasters said that day

The local office's own words before this flash flood warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

In the hours before

Special weather statement, Jul 11, 10:08 PM CDT, 4 hours 58 minutes before
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE WATERLOO IA
1000 PM CDT SAT JUL 11 1987

...SEVERE THUNDERSTORM WATCH UNTIL 1AM FOR PARTS OF NORTHERN IOWA...

AT 1000PM CDT NATIONAL WEATHER SERVICE RADAR AT WATERLOO WAS SHOWING
A NARROW BAND OF VERY STRONG THUNDERSTORMS IN NORTHEAST IOWA FROM 40
MILES NORTH OF WATERLOO NEAR FLOYD TO 20 MILES WEST OF WATERLOO NEAR
PARKERSBURG. THESE STORMS WILL BE IN THE NEW HAMPTON AND WAVERLY AREA
BETWEEN 1030 AND 1100 PM CDT.

THESE THUNDERSTORMS WILL PRODUCE BRIEF HEAVY RAIN...POSSIBLE SMALL
HAIL AND STRONG GUST WINDS AS THEY MOVE EAST AROUND 25 MILES
AN HOUR.

IN ADDITION TO THESE VERY STRONG STORMS SHOWERS AND THUNDERSHOWERS
WAS OCCURING OVER MUCH OF NORTHEAST AND NORTH CENTRAL IOWA.
FRANCISCO
Special weather statement, Jul 11, 10:50 PM CDT, 4 hours 16 minutes before
SPECIAL WEATHER STATEMENT AND RADAR SUMMARY
NATIONAL WEATHER SERVICE DES MOINES IA
1040PM CDT SAT JUL 11 1987

...SEVERE THUNDERSTORM WATCH FOR MUCH OF NORTHERN AND CENTRAL IOWA
   TIL 1 AM...
...FLASH FLOOD WATCH FOR WEST CENTRAL...SOUTHWEST...AND SOUTH CENTRAL
   IOWA TONIGHT...

...NO SEVERE WEATHER REPORTED IN IOWA BETWEEN 940 PM AND 1040 PM...

AT 1035 PM...SHOWERS AND INTENSE THUNDERSTORMS CONTINUED OVER ABOUT
THE NORTHERN HALF OF IOWA...GENERALLY ALONG AND NORTH OF A LINE FROM
DUBUQUE TO 40 MILES NORTH OF OMAHA.

THE MOST INTENSE STORMS WERE IN WESTERN IOWA...IN A 20 MILE WIDE BAND
THAT STRETCHED FROM JUST 30 MILES SOUTH OF SIOUX CITY TO SAC CITY...
ABOUT 60 MILES EAST OF SIOUX CITY.  BRIEF VERY HEAVY RAINS...SMALL PEA
TO MARBLE SIZED HAIL...AND WINDS OF 30 TO 40 MILES AN HOUR CAN BE
EXPECTED WITH THESE STORMS.

A SECOND CLUSTER OF STORMS WAS OVER NORTH CENTRAL IOWA NEAR FORT DODGE
AND AN INTENSE THUNDERSTORM WAS ALSO LOCAATED JUST NORTH OF WATERLOO.
THESE STORMS MAY ALSO PRODUCE BRIEF HEAVY RAINS AND SMALL HAIL.

THE SHOWERS AND STORMS WERE MOVING EAST AT 30 MILES AN HOUR...WHILE
THE ENTIRE AREA SAGGED SOUTH AT 5 TO 10 MILES AN HOUR.

SCOTT/MILLER
Special weather statement, Jul 12, 12:42 AM CDT, 2 hours 24 minutes before
SPECIAL WEATHER STATEMENT AND RADAR SUMMARY
NATIONAL WEATHER SERVICE DES MOINES IA
1240 AM CDT SUN JUL 12 1987

...SEVERE THUNDERSTORM WATCH FOR SOUTHWEST AND SOUTH CENTRAL IOWA
   UNTIL 5 AM...

...NO SEVERE WEATHER REPORTED IN IOWA BETWEEN 1130 PM AND 1230 AM...

AT 1230 AM...SHOWERS AND INTENSE THUNDERSTORMS CONTINUED OVER ABOUT
THE NORTHERN THREE QUATERS OF THE STATE...GENERALLY ALONG AND NORTH
OF LINE FROM OMAHA/COUNCIL BLUFFS TO 20 MILES NORTH OF DES MOINES TO
20 MILES NORTHWEST OF CEDAR RAPIDS TO 30 MILES NORTHWEST OF DUBUQUE.

THE MOST INTENSE STORMS WERE IN A 30 MILES WIDE AREA THAT EXTENDED
FROM OMAHA/COUNCIL BLUFFS TO 25 MILES NORTH OF DES MOINES TO 20 MILES
SOUTHEAST OF WATERLOO. BRIEF VERY HEAVY RAINS...PEA TO MARBLE SIZED
HAIL...AND WINDS OF 30 TO 40 MILES AN HOUR CAN BE EXPECTED WITH THESE
STORMS.

THE SHOWERS AND STORMS WERE MOVING EAST AT 30 MILES AN HOUR...WHILE
THE ENTIRE AREA SAGGED SOUTH AT 5 TO 10 MILES AN HOUR.

SCOTT/GOODSON
Special weather statement, Jul 12, 1:30 AM CDT, 1 hour 36 minutes before
URBAN FLOOD STATEMENT
NATIONAL WEATHER SERVICE DES MOINES IA
130 AM CDT SUN JUL 12 1987

AT 125 AM...SHOWERS AND INTENSE THUNDERSTORMS WERE NEARING THE CITIES
OF CEDAR RAPIDS AND DES MOINES.  THE LEADING EDGE EXTENDED FROM 5 MILES
WEST OF THE CEDAR RAPIDS AIRPORT TO 10 MILES NORTH OF THE DES MOINES
AIRPORT.

RAINFALL OF 1 TO 2 INCHES PER HOUR OVER THE NEXT 2 HOURS IS LIKELY.
FLOODING OF FAVORED LOW AREAS...UNDERPASSES AND ROADSIDE DITCHES WILL
LIKELY OCCUR.  MOTORISTS SHOULD NOT ATTEMPT TO CROSS RUNNING WATER OF
UNKNOW DEPTH.

PEA TO MARBLE-SIZED CAN BE EXPECTED AS WELL AS WINDS GUSTS TO 40 MILES
AN HOUR.

MYERS
Special weather statement, Jul 12, 1:47 AM CDT, 1 hour 19 minutes before
SPECIAL WEATHER STATEMENT AND RADAR SUMMARY
NATIONAL WEATHER SERVICE DES MOINES IA
145 AM CDT SUN JUL 12 1987

...SEVERE THUNDERSTORM WATCH FOR SOUTHWEST AND SOUTH CENTRAL IOWA
   UNTIL 5 AM...

...NO SEVERE WEATHER REPORTED IN IOWA BETWEEN 1230 AM AND 130 AM...

AT 135 AM...SHOWERS AND INTENSE THUNDERSTORMS CONTINUED OVER MUCH OF
IOWA NORTH OF LINE FROM THE SOUTHWEST CORNER OF THE STATE TO DES MOINES
TO CEDAR RAPIDS TO 30 MILES NORTHWEST OF DUBUQUE.

THE MOST INTENSE STORMS WERE IN A 40 MILES WIDE AREA THAT EXTENDED
FROM 30 MILES EAST OF OMAHA/COUNCIL BLUFFS TO 20 MILES NORTH OF
DES MOINES TO 15 MILES WEST OF CEDAR RAPIDS.  PEA TO MARBLE SIZED
HAIL...HEAVY RAIN AND STRONG GUSTY WINDS CAN BE EXPECTED WITH THESE
STORMS AS THEY MOVE EAST TO SOUTHEAST AT 25 MILES AN HOUR.

GOODSON
Special weather statement, Jul 12, 2:45 AM CDT, 21 minutes before
SPECIAL WEATHER STATEMENT AND RADAR SUMMARY
NATIONAL WEATHER SERVICE DES MOINES IA
245 AM CDT SUN JUL 12 1987

...SEVERE THUNDERSTORM WATCH FOR SOUTHWEST AND SOUTH CENTRAL IOWA
   UNTIL 5 AM...

...NO SEVERE WEATHER REPORTED IN IOWA BETWEEN 130 AM AND 230 AM...

AT 233 AM...SHOWERS AND INTENSE THUNDERSTORMS CONTINUED OVER MUCH OF
IOWA NORTH OF LINE FROM 20 MILES WEST OF LAMONI TO 20 MILES NORTHWEST
OF OTTUMWA TO 15 MILES NORTHWEST OF DUBUQUE. HEAVY RAIN...PEA TO
MARBLE SIZE HAIL HAVE BEEN REPORTED WITH THE THUNDERSTORMS.

THE MOST INTENSE STORMS WERE IN A 30 MILES WIDE AREA THAT EXTENDED
FROM 40 MILES WEST OF LAMONI 30 SOUTHEAST OF DES MOINES.  PEA TO
MARBLE SIZE HAIL...HEAVY RAIN AND STRONG GUSTY WINDS CAN BE EXPECTED
WITH THESE STORMS AS THE MOVE TO THE SOUTHEAST AT 25 MILES AN HOUR.

GOODSON

The office that day

Everything else NWS Des Moines, IA issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jul 11, 7:56 PM CDTSevere Thunderstorm WarningDMXChickasaw64 min
Jul 11, 8:54 PM CDTSevere Thunderstorm WarningDMXBuena Vista, Pocahontas36 min
Jul 11, 11:30 PM CDTSevere Thunderstorm WarningDMXMarshall, Story40 min
Jul 11, 11:50 PM CDTSevere Thunderstorm WarningDMXBlack Hawk, Grundy55 min
Jul 11, 11:57 PM CDTTornado WarningDMXMarshall28 min
Jul 12, 3:05 AM CDTFlash Flood WarningDMXRinggold, Taylor, Union4 hr
Jul 12, 3:05 AM CDTFlash Flood WarningDMXAdair, Adams65 min
Jul 12, 4:10 AM CDTFlash Flood WarningDMXAdams3 hr

Nearby

Flash Flood Warnings in Iowa, 1987Every flash flood warning in 1987

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive.